Objective Cryopreservation and regeneration of pollens of Sorbus pohuashanensis were investigatied.
Method An in vitro method was developed with experiments on medium formulation, light exposure, and pollen collection for the pollen germination rate determination.The germination rates of S.pohuashanensis pollens treated by various freezing and thawing procedures and different moisture contents before and after the treatments were compared.
Result (1) The medium for optimum pollen germination was found to consist of sucrose 100 g·L-1 and boric acid 100 mg·L-1 that delivered a rate of 72.42%. (2) Incubation in darkness yielded a germination rate of 77.24%, which was 8.96 percentage point higher than that under light exposure. (3) The vitality of pollens collected at 10 a.m. or 2 p.m. was significantly higher than other time in a day. (4) Among all cryopreservation methods tested, pre-freezing pollens at -20℃ for 30 min prior to submerging in liquid nitrogen for 24 h provided the greatest germination rate of 43.15% after thawing. (5) For thawing, soaking the frozen pollens in a 40℃ water bath for 5 min rendered the highest germination rate of 35.70%. (6) Moisture content of the pollens for the cryopreservation was determined to be 7.72% to result in the best germination rate of 31.53% after thawing.
Conclusion The cryopreservation conditions for S. pohuashanensis pollens as established would result in high viability and germination rate after storage.
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